Distinctive modulation patterns of functional brain connectivity of the default mode network by negative social emotions are associated with Alzheimer’s disease biomarkers in community‐dwelling older adults – cross‐sectional findings from the Age‐Well trial

Abstract

AbstractBackgroundRecent evidence in Alzheimer’s diseases suggests that early dysfunction of emotional processing may precede the onset of cognitive decline and dementia. Altered functional brain connectivity patterns also occur along with other brain changes many years before clinical AD symptoms.MethodWe combined baseline multimodal neuroimaging data from cognitively healthy older adults (N = 125) enrolled in the Age‐Well trial of the Medit‐Ageing study. The aim was to elucidate the relationship of five AD risk factors (amyloid‐beta depositions and hypoperfusion with AV45‐PET, hippocampal atrophy, cognition with PACC‐5, cardiovascular risk with CAIDE) with carry‐over effects of social emotions and related brain functions. Using k‐means clustering analysis with the AD risk factors, we first defined participants with higher or lower preclinical risk for AD. We then used functional Magnetic Resonance Imaging to probe functional brain connectivity in resting periods following negative socio‐emotional videos in the SoVT‐Rest paradigm.ResultParticipants with a higher preclinical AD risk showed reduced positivity bias in affect ratings and reduced connectivity patterns between control‐related frontal brain regions and emotion‐related limbic regions (amygdala). In particular, this fronto‐limbic connectivity was associated with higher cardiovascular risk on the CAIDE composite score.ConclusionWe find evidence for changes in post‐emotion functional recovery patterns in fronto‐limbic brain networks in at‐risk individuals for AD. These changes might reflect impaired emotion regulation processes.